A Facebook craze spreading across France has left a young man dead and another severely injured.

Police said a 19-year-old drowned after driving his bicycle into a river in a town in western Brittany while a friend filmed him.

Another youth suffered life-changing injuries after diving headfirst into shallow water near Calais.

The craze has seen people challenging friends to jump fully clothed into rivers and the sea and film it within 48 hours - or offer dinner at a restaurant.

A warning posted by police on Facebook said: "Don't be influenced by a stupid phenomenon of the moment."

Deputy prosecutor Igor Souchu criticised the "dramatic and stupid" game after the death in Beganne.

Image:POlice said the man was dragged under the water by his bike

Police chief Colonel Sylvain Laniel said: "The young man drowned after being thrown into the water with his bicycle as part of a challenge.

"The victim had seen fit to tie his bike to his leg to recover, but there were six-metres deep and could not go back."

Mr Souchu added: "The victim repeatedly attempted to resurface but could not because of the weight of the bike."

The warning follows widespread concern over the global spread of the Neknomination craze - an online drinking game in which people filmed themselves downing a drink in various situations before nominating friends to do the same.